One can only export the entire timeline, not individual clips from it.
You can, however, select the edited clip and then Edit/Copy, Edit/Paste, it into a newly created project, and export it from that project. Or you can Edit/Copy, Edit/Paste, the entire project into a newly created project, and then delete all the clips except the edited one. Then you can export the edited one.
Another way to make a duplicate of the project is to move your cursor over its icon in the project browser screen. That will reveal a little circle with dots in it to the right of the title. Click on the circle and a drop down menu will appear that contains a Duplicate Project option. Click on Duplicate Project. From within the duplicated project, delete all the clips except the edited one and then export.
-- Rich